Cooling Fan with Dual Rotation Directions

ABSTRACT

A cooling fan with dual rotation directions includes a fan frame unit, a driving control unit and an impeller. The fan frame unit has an air channel having first and second air-guiding openings on two sides of the air channel. A base is disposed between the first and second air-guiding openings. A first stationary blade unit is disposed at the first air-guiding opening and a second stationary blade unit is disposed at the second air-guiding opening. The driving control unit has a stator, a driving circuit and a rotation direction control circuit, wherein the stator is disposed on the base of the fan frame unit and the driving circuit is electrically connected to the stator and the rotation direction control circuit. The impeller is rotatably coupled with the stator of the driving control unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a cooling fan and, more particularly, to a cooling fan having an impeller with dual rotation directions and capable of controlling the timing at which the rotation direction of the impeller is switched.

2. Description of the Related Art

A conventional cooling fan generally has a fan frame having a base disposed therein. The base is coupled with a motor for driving an impeller to rotate. Generally, the base is connected to the fan frame at an air outlet via a plurality of ribs. When the impeller drives the air to pass through the air outlet, the ribs tend to hinder the air from entering the conventional cooling fan, thus decreasing the performance of the conventional cooling fan.

In light of this problem, referring to FIG. 1, Taiwanese Patent No. 488497 discloses an apparatus for increasing air pressure and guiding airflows of the conventional cooling fan. The apparatus 9 includes an airflow guiding device 91 resembling blades (which is also known as stationary blades). The airflow guiding device 91 may be disposed at an air outlet of the conventional cooling fan opposing to a plurality of blades 92 of the conventional cooling fan. In such an arrangement, when the blades 92 drive the air to pass through the air outlet of the conventional cooling fan, the airflow guiding device 91 may increase the pressure of the air flowing out of the conventional cooling fan.

Taiwanese Patent No. M388570 discloses another conventional cooling fan with dual rotation directions. The conventional cooling fan includes a blade unit, an electric machinery and a controller. The controller can control the blade unit to rotate in a forward or reverse direction via the electric machinery, thereby performing the cooling and dust exhaustion operations of the conventional cooling fan.

When the conventional cooling fan rotates in a forward direction for cooling purpose, the apparatus 9 does increase the air pressure of the air outlet of the conventional cooling fan. However, when the conventional cooling fan rotates in a reverse direction for dust exhaustion, the air outlet of the conventional cooling fan will become an entrance of airflows and an air inlet of the conventional cooling fan will become an exit of airflows. Since the air inlet of the conventional cooling fan is not designed with any structure capable of increasing the pressure of the air passing therethrough, the dust exhaustion will not be performed in an efficient way due to the small air pressure. In overall, the apparatus 9 provides the conventional cooling fan different air-driving effects when the conventional cooling fan rotates in different direction. For example, the apparatus 9 can drive the air in a larger strength when the conventional cooling fan rotates in the forward direction for cooling purpose, but drives the air in a relatively small strength when the conventional cooling fan rotates in the reverse direction for dust exhaustion. This results in poorer performance in dust exhaustion.

SUMMARY OF THE INVENTION

It is therefore the primary objective of this invention to provide a cooling fan with dual rotation directions which provides almost the same air-driving effect when the cooling fan rotates in different directions.

It is another objective of this invention to provide a cooling fan with dual rotation directions that, based on almost the same air-driving effect in different rotation directions, can be mounted on an electronic product in a flexible way to achieve assembly convenience.

The invention discloses a cooling fan with dual rotation directions, which includes a fan frame unit, a driving control unit and an impeller. The fan frame unit has an air channel having first and second air-guiding openings on two sides of the air channel. A base is disposed between the first and second air-guiding openings. A first stationary blade unit is disposed at the first air-guiding opening and a second stationary blade unit is disposed at the second air-guiding opening. The driving control unit has a stator, a driving circuit and a rotation direction control circuit, wherein the stator is disposed on the base of the fan frame unit and the driving circuit is electrically connected to the stator and the rotation direction control circuit. The impeller is rotatably coupled with the stator of the driving control unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 shows a diagram of an apparatus for increasing air pressure and guiding airflows of a conventional cooling fan.

FIG. 2 shows an exploded diagram of a cooling fan with dual rotation directions according to a preferred embodiment of the invention.

FIG. 3 shows a side cross-sectional diagram of the cooling fan with dual rotation directions of the invention.

FIG. 4 shows an implementation of a fan frame unit of the cooling fan with dual rotation directions of the invention.

FIG. 5 shows a side cross-sectional diagram of the cooling fan with dual rotation directions of the invention, in which the cooling fan includes a first stationary blade unit and a second stationary blade unit comprising a plurality of stationary blades having a different oblique angle from a plurality of stationary blades of the first stationary blade unit.

FIG. 6 shows a side cross-sectional diagram of the cooling fan with dual rotation directions of the invention, in which both the first and second stationary blade units have an air-guiding portion.

In the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the term “first”, “second”, “third”, “fourth”, “inner”, “outer” “top”, “bottom” and similar terms are used hereinafter, it should be understood that these terms refer only to the structure shown in the drawings as it would appear to a person viewing the drawings, and are utilized only to facilitate describing the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 2 and 3, a cooling fan with dual rotation directions of the invention at least includes a fan frame unit 1, a driving control unit 2 and an impeller 3. The fan frame unit 1 is coupled with the driving control unit 2 when the driving control unit 2 is disposed in the fan frame unit 1. The impeller 3 is rotatably coupled with the driving control unit 2 such that the driving control unit 2 can control the impeller 3 to rotate in a forward or reverse direction.

The fan frame unit 1 consists of at least a hollow frame and has an air channel 11. The air channel 11 has a first air-guiding opening 111 and a second air-guiding opening 112 on two sides thereof, with a base 12 disposed between the first air-guiding opening 111 and second air-guiding opening 112. The first air-guiding opening 111 has a first stationary blade unit 13 disposed thereat and the second air-guiding opening 112 has a second stationary blade unit 14 disposed thereat.

In the embodiment, the fan frame unit 1 consists of a first frame 1 a and a second frame 1 b. The first frame 1 a and second frame 1 b may be detachably assembled together so that the interior spaces of the first frame 1 a and second frame 1 b may communicate with each other to form the air channel 11. The first air-guiding opening 111 is located in the first frame 1 a and the second air-guiding opening 112 is located in the second frame 1 b. The base 12 is located in the first frame 1 a. Both the first stationary blade unit 13 and second stationary blade unit 14 consist of a plurality of stationary blades. The first stationary blade unit 13 is disposed in the first frame 1 a and adjoins the first air-guiding opening 111, and the second stationary blade unit 14 is disposed in the second frame 1 b and adjoins the second air-guiding opening 112. The base 12 is coupled with an inner circumferential wall of the first frame 1 a via the stationary blades of the first stationary blade unit 13.

Although the fan frame unit 1 is shown to consist of the first frame 1 a and second frame 1 b, more than two frames can be used to form the fan frame unit 1. For example, referring to FIG. 4, the fan frame unit 1 may consist of the first frame 1 a, the second frame 1 b and a third frame 1 c, with the third frame 1 c sandwiched between the first frame 1 a and second frame 1 b. Therefore, the fan frame unit 1 is allowed to comprise at least one hollow frame if it won't affect the assembly of the driving control unit 2 and impeller 3, as can be readily appreciated by one skilled in this art.

The driving control unit 2 has a stator 21, a driving circuit 22 and a rotation direction control circuit 23. The stator 21 is disposed on the base 12 of the fan frame unit 1 and rotatably coupled with the impeller 3. The driving circuit 22 is electrically connected to the stator 21. The rotation direction control circuit 23 is electrically connected to the driving circuit 22. Based on this, the rotation direction control circuit 23 can control the forward or reverse rotation of the impeller 3 via the driving circuit 22. The driving circuit 22 and rotation direction control circuit 23 can be integrated into an integrated chip (IC).

The impeller 3 has a hub 31 rotatably coupled with the stator 21 of the driving control unit 2. The hub 31 has a plurality of vanes 32 on an outer circumferential wall thereof. The vanes 32 drive the air to pass through the first air-guiding opening 111 and second air-guiding opening 112 when the driving control unit 2 drives the hub 31 to rotate (one skilled in the art may readily appreciate that the driving control unit 2 drives the hub 31 to rotate under alternating magnetic fields, so it is not described herein again).

When the cooling fan with dual rotation directions of the invention is in use, the driving control unit 2 may control the hub 31 to rotate in the forward or reverse direction. Thus, one of the first air-guiding opening 111 and second air-guiding opening 112 will serve as an air inlet, depending on the rotation direction of the cooling fan. Based on dual rotation directions of the cooling fan, both the first air-guiding opening 111 and second air-guiding opening 112 can serve as an air inlet and an air outlet. For example, both the first air-guiding opening 111 and second air-guiding opening 112 may serve the cooling purpose. Specifically, the cooling fan may drive and guide the internal air of the fan frame unit 1 to a heat-emitting source for cooling operation when the cooling fan rotates in the forward direction, as well as to another heat-emitting source for cooling operation when the cooling fan rotates in the reverse direction. In another application, the first air-guiding opening 111 may serve the cooling purpose and the second air-guiding opening 112 may serve the dust exhaustion purpose.

For example, the cooling fan with dual rotation directions of the invention may be mounted on an electronic product when the first air-guiding opening 111 of the fan frame unit 1 faces a predetermined portion of the electronic product where heat is constantly emitted. When the electronic product emits the heat during operation thereof, the rotation direction control circuit 23 of the driving control unit 2 can send a control signal to the driving circuit 22 which, in turn, drives the stator 21 to generate magnetic fields upon receipt of the control signal. The generated magnetic fields can drive the impeller 3 to rotate in a first direction (which can be the reverse or forward direction), drawing the external air into the fan frame unit 1 via the second air-guiding opening 112. The impeller 3 guides the drawn air to travel in the air channel 11 and the internal air of the fan frame unit 1 is then exhausted via the first air-guiding opening 111 and guided to the predetermined portion of the electronic product for cooling operation. In this embodiment, the first air-guiding opening 111 serves as an air outlet and the second air-guiding opening 112 serve as an air inlet.

However, when the cooling fan of the invention operates in a long time, dust contained in the air will accumulate in the fan frame unit 1. For example, the dust may remain on the first air-guiding opening 111, second air-guiding opening 112 or vanes 32 of the impeller 3 and so on. At this point, the rotation direction control circuit 23 of the driving control unit 2 can send another control signal to the driving circuit 22 which, in turn, drives the stator 21 to generate magnetic fields. Due to the switch of control signal, the generated magnetic fields will drive the impeller 3 to rotate in a second direction opposite to the first direction, drawing the external air into the fan frame unit 1 via the first air-guiding opening 111. The impeller 3 guides the drawn air to travel in the air channel 11 and the internal air of the fan frame unit 1 is then exhausted via the second air-guiding opening 112. In this way, the dust accumulated in the fan frame unit 1 can be blown away by the airflows. In this embodiment, the first air-guiding opening 111 serves as an air inlet and the second air-guiding opening 112 serve as an air outlet.

The cooling fan with dual rotation directions of the invention is characterized in that the first air-guiding opening 111 of the fan frame unit 1 is provided with the first stationary blade unit 13 and the second air-guiding opening 112 of the fan frame unit 1 is provided with the second stationary blade unit 14. Thus, the first stationary blade unit 13 may increase the pressure of the air passing through the first air-guiding opening 111 when the first air-guiding opening 111 serves as an air outlet. Similarly, the second stationary blade unit 14 may increase the pressure of the air passing through the second air-guiding opening 112 when the second air-guiding opening 112 serves as an air outlet.

However, when the first air-guiding opening 111 serves as an air outlet, the second stationary blade unit 14 disposed at the second air-guiding opening 112 will hinder the air from entering the fan frame unit 1. Similarly, when the second air-guiding opening 112 serves as an air outlet, the first stationary blade unit 13 disposed at the first air-guiding opening 111 will also hinder the air from entering the fan frame unit 1. Although the first stationary blade unit 13 hinders the air from entering the fan frame unit 1 when the second air-guiding opening 112 serves as an air outlet, the first stationary blade unit 13 does increase the pressure of the air flowing out of the fan frame unit 1 at the same moment. Similarly, although the second stationary blade unit 14 hinders the air from entering the fan frame unit 1 when the first air-guiding opening 111 serves as an air outlet, the second stationary blade unit 14 does increase the pressure of the air flowing out of the fan frame unit 1 at the same moment. Therefore, the cooling fan of the invention can provide almost the same air-driving effect at the first air-guiding opening 111 and second air-guiding opening 112 regardless of rotation direction of the impeller 3. In other words, the cooling fan with dual rotation directions of the invention can provide a heat-emitting source almost the same cooling effect at the first air-guiding opening 111 and second air-guiding opening 112. Alternatively, when the first air-guiding opening 111 serves the cooling purpose and the second air-guiding opening 112 serves the dust exhaustion purpose, the cooling operation will be as efficient as the dust exhaustion operation. This differs from the conventional cooling fan that provides a better cooling efficiency than the dust exhaustion efficiency. Although the first air-guiding opening 111 and second air-guiding opening 112 of the cooling fan may not drive the internal air of the fan frame unit 1 in a most efficient way, they do provide the required air-driving effect.

More importantly, since the cooling fan with dual rotation directions of the invention provides almost the same air-driving effect at the first air-guiding opening 111 and second air-guiding opening 112 regardless of rotation direction of the cooling fan, the first air-guiding opening 111 or the second air-guiding opening 112 can be chosen to face the electronic product while mounting the cooling fan on the electronic product. In this way, the cooling fan of the invention allows either air-guiding opening to face the electronic product while mounting the cooling fan on the electronic product. This prevents the cooling fan from being mounted on the electronic product in an incorrect way. Therefore, it will not be required to remount the cooling fan on the electronic product due to the incorrect mounting of the cooling fan, thus improving the assembly convenience of the cooling fan.

The cooling fan with dual rotation directions of the invention may include one or more of the following secondary features for further improvement, as described below.

The first stationary blade unit 13 is disposed in a different direction from the second stationary blade unit 14 in an axial direction of the impeller 3. Specifically, take the cooling fans shown in FIGS. 3 and 6 as an example, the first stationary blade unit 13 is disposed at the first air-guiding opening 111 in a way that the stationary blades of the first stationary blade unit 13 extend from bottom-right to top-left corners in cross sections thereof, whereas the second stationary blade unit 14 is disposed at the second air-guiding opening 112 in a way that the stationary blades of the second stationary blade unit 14 extend from bottom-left to top-right corners in cross sections thereof. In other words, the first stationary blade unit 13 extends in an opposite direction to the second stationary blade unit 14 in the axial direction of the impeller 3. One skilled in this art may readily appreciate that the oblique angle of the stationary blades of the first stationary blade unit 13 and second stationary blade unit 14 with respect to the axial direction of the impeller 3 may be properly adjusted according to the angle of the vanes 32 of the impeller 3 (for example, the oblique angle of the stationary blades of the first stationary blade unit 13 is different from that of the stationary blades of the second stationary blade unit 14 in both FIGS. 3 and 5). Therefore, the structure of the first stationary blade unit 13 and second stationary blade unit 14 may be designed in a flexible way that conforms to the angle of the vanes 32 of the impeller 3 for achieving best air-driving effect at the first air-guiding opening 111 and second air-guiding opening 112, regardless of rotation direction of the cooling fan. Alternatively, based on the fact that the first stationary blade unit 13 is disposed in the different direction from the second stationary blade unit 14 in the axial direction of the impeller 3, the stationary blades of the first stationary blade unit 13 can have the same oblique angle as those of the second stationary blade unit 14. This allows the first stationary blade unit 13 and second stationary blade unit 14 to be manufactured using a single mold for cost reduction.

Referring to FIG. 6, the first stationary blade unit 13 may further include an air-guiding portion 131 at a center thereof. Based on this, when the first air-guiding opening 111 serves as an air inlet drawing the external air into the air channel 11, the air-guiding portion 131 may efficiently guide the external air to pass through the first stationary blade unit 13. Similarly, the second stationary blade unit 14 may further include an air-guiding portion 141 at a center thereof. Based on this, when the second air-guiding opening 112 serves as an air inlet drawing the external air into the air channel 11, the air-guiding portion 141 may efficiently guide the external air to pass through the second stationary blade unit 14. With the arrangement of the air-guiding portions 131 and 141, the cooling or dust exhaustion efficiency of the cooling fan can be improved.

In conclusion, the cooling fan with dual rotation directions of the invention does provide almost the same air-driving effect at both first and second air-guiding openings 111 and 112 no matter which direction the cooling fan rotates in. As such, desired air-driving effect can be provided no matter which of the first and second air-guiding openings 111 and 112 is used as an air outlet. Also, the invention allows the cooling fan to be mounted on the electronic product in a convenient way.

Although the invention has been described in detail with reference to its presently preferable embodiment, it will be understood by one of ordinary skill in the art that various modifications can be made without departing from the spirit and the scope of the invention, as set forth in the appended claims. 

1. A cooling fan with dual rotation directions, comprising: a fan frame unit having an air channel with first and second air-guiding openings on two sides of the air channel, wherein a base is disposed between the first and second air-guiding openings, a first stationary blade unit is disposed at the first air-guiding opening and a second stationary blade unit is disposed at the second air-guiding opening; a driving control unit having a stator, a driving circuit and a rotation direction control circuit, wherein the stator is disposed on the base of the fan frame unit, the driving circuit is electrically connected to the stator and the rotation direction control circuit; and an impeller rotatably coupled with the stator of the driving control unit.
 2. The cooling fan with dual rotation directions as claimed in claim 1, wherein the fan frame unit comprises a first frame and a second frame detachably assembled to the first frame to form the air channel, the first air-guiding opening is located in the first frame and the second air-guiding opening is located in the second frame, and the base is located in the first frame.
 3. The cooling fan with dual rotation directions as claimed in claim 2, wherein both the first stationary blade unit and the second stationary blade unit comprise a plurality of stationary blades.
 4. The cooling fan with dual rotation directions as claimed in claim 3, wherein the base is coupled with an inner circumferential wall of the first frame via the stationary blades of the first stationary blade unit.
 5. The cooling fan with dual rotation directions as claimed in claim 2, wherein the fan frame unit further comprises a third frame sandwiched between the first frame and the second frame.
 6. The cooling fan with dual rotation directions as claimed in claim 1, wherein the first stationary blade unit is disposed in a different direction from the second stationary blade unit in a way that the first and second stationary blade units extend in opposite directions from each other in an axial direction of the impeller.
 7. The cooling fan with dual rotation directions as claimed in claim 1, wherein an oblique angle of the stationary blades of the first stationary blade unit with respect to an axial direction of the impeller is different from that of the stationary blades of the second stationary blade unit.
 8. The cooling fan with dual rotation directions as claimed in claim 6, wherein an oblique angle of the stationary blades of the first stationary blade unit with respect to the axial direction of the impeller is different from that of the stationary blades of the second stationary blade unit.
 9. The cooling fan with dual rotation directions as claimed in claim 6, wherein an oblique angle of the stationary blades of the first stationary blade unit with respect to the axial direction of the impeller is the same as that of the stationary blades of the second stationary blade unit.
 10. The cooling fan with dual rotation directions as claimed in claim 1, wherein the first stationary blade unit further comprises an air-guiding portion at a center thereof.
 11. The cooling fan with dual rotation directions as claimed in claim 1, wherein the second stationary blade unit further comprises an air-guiding portion at a center thereof.
 12. The cooling fan with dual rotation directions as claimed in claim 1, wherein the driving circuit and the rotation direction control circuit are integrated into an integrated chip. 